UA Action Points seem to be a good fit for Dark Sun heroes (not NPCs).
I’d keep it the same with some minor alterations.
*No Spell Recall.
*No free metamagic casting via Action Points (see Metamagic Feats).
*1 action point per level of the PC, refreshed daily instead of the fixed number of action points usable per level under the UA rules.
It makes it a lot cooler and heroic. When Rikus threw the Heartwood Spear, he was assuredly using action points.